1,443 research outputs found

    Nerve Agent Hydrolysis Activity Designed into a Human Drug Metabolism Enzyme

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    Organophosphorus (OP) nerve agents are potent suicide inhibitors of the essential neurotransmitter-regulating enzyme acetylcholinesterase. Due to their acute toxicity, there is significant interest in developing effective countermeasures to OP poisoning. Here we impart nerve agent hydrolysis activity into the human drug metabolism enzyme carboxylesterase 1. Using crystal structures of the target enzyme in complex with nerve agent as a guide, a pair of histidine and glutamic acid residues were designed proximal to the enzyme's native catalytic triad. The resultant variant protein demonstrated significantly increased rates of reactivation following exposure to sarin, soman, and cyclosarin. Importantly, the addition of these residues did not alter the high affinity binding of nerve agents to this protein. Thus, using two amino acid substitutions, a novel enzyme was created that efficiently converted a group of hemisubstrates, compounds that can start but not complete a reaction cycle, into bona fide substrates. Such approaches may lead to novel countermeasures for nerve agent poisoning

    Exercise training enhanced myocardial endothelial nitric oxide synthase (eNOS) function in diabetic Goto-Kakizaki (GK) rats

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    Abstract Background Different mechanisms of diabetic-induced NO dysfunction have been proposed and central to most of them are significant changes in eNOS function as the rate-limiting step in NO bioavailability. eNOS exists in both monomeric and dimeric conformations, with the dimeric form catalyzing the synthesis of nitric oxide, while the monomeric form catalyzes the synthesis of superoxide (O2-). Diabetic-induced shifts to decrease the dimer:monomer ratio is thought to contribute to the degradation of nitric oxide (NO) bioavailability. Exercise has long been useful in the management of diabetes. Although exercise-induced increases expression of eNOS has been reported, it is unclear if exercise may alter the functional coupling of eNOS. Methods To investigate this question, Goto-Kakizaki rats (a model of type II diabetes) were randomly assigned to a 9-week running program (train) or sedentary (sed) groups. Results Exercise training significantly (p 4), but not in the presence of exogenous BH4. Exercise training also significantly decreased NADPH-dependent O2- activity. Conclusion Exercise-induced increased eNOS dimerization resulted in an increased coupling of the enzyme to facilitate production of NO at the expense of ROS generation. This shift that could serve to decrease diabetic-related oxidative stress, which should serve to lessen diabetic-related complications.</p

    Elastic Chain in a Random Potential: Simulation of the Displacement Function <(u(x)u(0))2><(u(x)-u(0))^2> and Relaxation

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    We simulate the low temperature behaviour of an elastic chain in a random potential where the displacements u(x)u(x) are confined to the {\it longitudinal} direction (u(x)u(x) parallel to xx) as in a one dimensional charge density wave--type problem. We calculate the displacement correlation function g(x)=<(u(x)u(0))2>g(x)=< (u(x)-u(0))^2> and the size dependent average square displacement W(L)=W(L)=. We find that g(x)x2ηg(x)\sim x^{2\eta} with η3/4\eta\simeq3/4 at short distances and η3/5\eta\simeq3/5 at intermediate distances. We cannot resolve the asymptotic long distance dependence of gg upon xx. For the system sizes considered we find g(L/2)WL2χg(L/2)\propto W\sim L^{2\chi} with χ2/3\chi\simeq2/3. The exponent η3/5\eta\simeq3/5 is in agreement with the Random Manifold exponent obtained from replica calculations and the exponent χ2/3\chi\simeq2/3 is consistent with an exact solution for the chain with {\it transverse} displacements (u(x)u(x) perpendicular to xx).The distribution of nearest distances between pinning wells and chain-particles is found to develop forbidden regions.Comment: 19 pages of LaTex, 6 postscript figures available on request, submitted to Journal of Physics A, MAJOR CHANGE

    Role of the α1 blocker doxazosin in alcoholism: a proof-of-concept randomized controlled trial

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    Evidence suggests that the norepinephrine system represents an important treatment target for alcohol dependence (AD) and the α1-blocker prazosin may reduce alcohol drinking in rodents and alcoholic patients. The α1-blocker doxazosin demonstrates a more favorable pharmacokinetic profile than prazosin, but has never been studied for AD. A double-blind placebo-controlled randomized clinical trial was conducted in AD individuals seeking outpatient treatment. Doxazosin or matched placebo was titrated to 16 mg/day (or maximum tolerable dose). Drinks per week (DPW) and heavy drinking days (HDD) per week were the primary outcomes. Family history density of alcoholism (FHDA), severity of AD and gender were a priori moderators. Forty-one AD individuals were randomized, 30 (doxazosin = 15) completed the treatment phase and 28 (doxazosin = 14) also completed the follow-up. There were no significant differences between groups on DPW and HDD per week. With FHDA as a moderator, there were significant FHDA × medication interactions for both DPW (pcorrected = 0.001, d = 1.18) and HDD (pcorrected = 0.00009, d = 1.30). Post hoc analyses revealed that doxazosin significantly reduced alcohol drinking in AD patients with high FHDA and by contrast increased drinking in those with low FHDA. Doxazosin may be effective selectively in AD patients with high FHDA. This study provides preliminary evidence for personalized medicine using α1-blockade to treat AD. However, confirmatory studies are required

    Evaluation Capacity Building in Pretrial Diversion Services: A Case Study

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    Despite increasing use of adult pretrial diversion programs in recent years, the limited capacity to produce, analyze, and translate evaluation data in pretrial diversion programs has frequently resulted in policy and programmatic decisions being made on the basis of little or no empirical information. This paper presents a case study of the development of an evaluation system for the Alaska Pretrial Intervention (PTI) program of the Alaska Department of Law which can generate timely results for policymaking as well as monitor staff productivity.Alaska Department of LawIntroduction / Alaska Pretrial Program / Development of an Evaluation Effort / Conclusions / Note / Bibliography / Map of PTI program location

    Pertussis Seroepidemiology in Women and Their Infants in Sarlahi District, Nepal.

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    Background Infants are at greatest risk for pertussis morbidity and mortality. Maternal vaccination during pregnancy has been shown to prevent pertussis in young infants in high- and middle-income countries. However, data on the levels of maternal pertussis antibodies and the efficiency of transplacental transfer in low-income South Asian settings are limited. Objective To estimate the prevalence of maternal pertussis antibodies and the efficiency of transplacental transfer in rural southern Nepal. Design/methods Paired maternal-infant blood samples were collected from a subsample of participants in a randomized, controlled trial of maternal influenza immunization (n = 291 pairs). Sera were tested by enzyme-linked immunosorbent assays for pertussis toxin, filamentous hemagglutinin, pertactin, and fimbriae. Maternal and infant pertussis antibody levels and transplacental transfer efficiency were determined and potential factors associated with both were assessed. Results Elevated maternal antibodies to pertussis toxin, suggesting recent pertussis infection, were rarely detected (4%, tested n = 305). However, paired maternal-cord sera were highly correlated across all antibodies; transplacental antibody transfer ratios for pertussis toxin were 1.14 (n = 291, 95% CI 1.07–1.20); filamentous hemagglutinin 1.10 (n = 120, 95% CI: 1.01–1.20); fimbriae 2/3 1.05 (n = 120, 95% CI: 0.96–1.15) and pertactin 0.96 (n = 289, 95% CI: 0.91–1.00). Older gestational age was associated with increased pertussis toxin and decreased fimbriae 2/3 antibody transport. Conclusions A low prevalence of maternal antibody to all four pertussis antigens was noted in Nepal, but transplacental antibody transfer was efficient. No consistent demographic factors were associated with elevated maternal antibody levels or efficiency of transplacental transfer. If an increase in infant pertussis disease burden was detected in this population, maternal immunization could be an effective intervention to prevent disease in early infancy

    Exposure to the World Trade Center Disaster and 9/11-Related Post-Traumatic Stress Disorder and Household Disaster Preparedness

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    Objective In a population with prior exposure to the World Trade Center disaster, this study sought to determine the subsequent level of preparedness for a new disaster and how preparedness varied with population characteristics that are both disaster-related and non-disaster-related. Methods The sample included 4496 World Trade Center Health Registry enrollees who completed the Wave 3 (2011-2012) and Hurricane Sandy (2013) surveys. Participants were considered prepared if they reported possessing at least 7 of 8 standard preparedness items. Logistic regression was used to determine associations between preparedness and demographic and medical factors, 9/11-related post-traumatic stress disorder (PTSD) assessed at Wave 3, 9/11 exposure, and social support. Results Over one-third (37.5%) of participants were prepared with 18.8% possessing all 8 items. The item most often missing was an evacuation plan (69.8%). Higher levels of social support were associated with being prepared. High levels of 9/11 exposure were associated with being prepared in both the PTSD and non-PTSD subgroups. Conclusions Our findings indicate that prior 9/11 exposure favorably impacted Hurricane Sandy preparedness. Future preparedness messaging should target people with low social support networks. Communications should include information on evacuation zones and where to find information about how to evacuate

    Shared characteristics underpinning C 4 leaf maturation derived from analysis of multiple C 3 and C 4 species of Flaveria

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    Most terrestrial plants use C3 photosynthesis to fix carbon. In multiple plant lineages a modified system known as C4 photosynthesis has evolved. To better understand the molecular patterns associated with induction of C4 photosynthesis, the genus Flaveria that contains C3 and C4 species was used. A base to tip maturation gradient of leaf anatomy was defined, and RNA sequencing was undertaken along this gradient for two C3 and two C4Flaveria species. Key C4 traits including vein density, mesophyll and bundle sheath cross-sectional area, chloroplast ultrastructure, and abundance of transcripts encoding proteins of C4 photosynthesis were quantified. Candidate genes underlying each of these C4 characteristics were identified. Principal components analysis indicated that leaf maturation and the photosynthetic pathway were responsible for the greatest amount of variation in transcript abundance. Photosynthesis genes were over-represented for a prolonged period in the C4 species. Through comparison with publicly available data sets, we identify a small number of transcriptional regulators that have been up-regulated in diverse C4 species. The analysis identifies similar patterns of expression in independent C4 lineages and so indicates that the complex C4 pathway is associated with parallel as well as convergent evolution
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